Fastener device



June 26, 1962 c. J. DE CARO FASTENER DEVICE 2 Sheets-Sheet 1 Filed June 18, 1958 FIG.

FIG. 5

57 INVENTOR.

CHARLES J. DECARO BY ArT om/Ers June 26, 1962 c J.. DE CARO 3,040,326 FASTENER DEVICE Filed June 18, 1958 2 Sheets-Sheet 2 INVENTOR. CHARLES J. DECARO I 4 g g Q Q) i ,1; I Armmvers 3,040,326 FASTENEF: DEVICE Charles J. Ee \Caro, Erecksviiie, Ghio, assignor to Giin Mathieson Chemical (Importation, East Alton, lit, a corporation of Virginia Filed June 18, 1958, Ser. No. 742,874 8 Claims. (Cl. 1-445) This invention relates to tools and more specifically to explosive operated tools.

One type of such tool includes either a work impacting piston or a tool-carrying ram driven at high velocity. Explosive tools of this type utilizing blank cartridges are shown in US. Patents 1,466,968 (Smith); 2,008,362 (Littiehale) and 2,221,157 (Temple). I-Ieretofore many of these have included some additional structure to mollify the impact of the piston, the stopping of which Without breaking of part of the tool presents a problem encountered in this art. The problem is particularly serious in those instances where inadvertently no part to be Worked on is emplaced in the tool so that the piston collides With full force against the piston stop at the muzzle of the tool 'barrel, and also in those instances where the resistance offered by the piece worked upon or driven into varies from piece to piece or from area to area. Heretofore used shock absorbers, such as air chambers and rubber buffers have the disadvantage of either requiring entirely too close a tolerance and/ or suffering impairment under the heavy blow and high temperatures encountered. Some violently recoil the piston.

Therefore, one object of this invention is to provide an explosive actuated tool having new and improved shock absorbing means overcoming the foregoing and other objections encountered in prior art devices of this type. Another object is to provide a new and improved apparatus operated by a blank cartridge for driving a punch or a ram with high force and velocity down the bore of a barrel. Still another object is to provide in explosive actuated punching tools a built-in shock absorbing structure for cushioning any collision which may occur between the tool parts. The foregoing and other objects of this invention are accomplished in accordance with this invention by the provision of a new and improved barrel structure.

Specifically, it has been found that lamination or subdivision of the barrel in the manner and relationship described herein results in very high resistance of the barrel to breakage in the event that the tool carrying piston or ram strikes the piston retaining stop at the muzzle of the barrel.

The laminations may take various forms. They may take the form of a closely wound helical coil or spiral segments with quadrilateral or D-shaped cross sectional turns in contiguity with each other. They may take the form of arcuate wedge-shaped segments extending longitudinally and laid up side-by-side to extend circumferentially over 360 and to complete the barrel. Another form is that of a bundle of strands such as wires of a suitable metal such as steel. Still another form effectively increases the length of the barrel and more particularly consists of a coaxial arrangement of relatively thin tubes interconnected at the ends so as to transmit and effectively absorb the impact of the piston. All forms contemplated subdivide substantially all of the barrel at least in the lengthwise direction. The degree of lamination is such as to provide a sufficient number or suffi- ,cient effective length of relatively long and relatively thin or slender stress-absorbing members so that the shock is taken up by elastic deformation sufiiciently to avoid any over-stress or fracture. The construction is such that normally the barrelis a closed structure which in certain embodiments permits a separation between the ii ater r smears Patented June 26, 1%62 segments or turns constituting the lamination so as to provide a venting near the end of the stroke of the piston.

The invention is better understood from the following description of various preferred specific embodiments and the accompanying drawing of the same wherein:

'FIGURE 1 is a longitudinal cross sectional view illustrating one preferred embodiment;

FIGURE 2 is a longitudinal view showing a second embodiment;

FIGURE 3 is a transverse cross sectional view taken on line IIL-III of FIGURE 2;

FIGURE 4 is a transverse cross sectional view taken looking up the barrel bore toward the breech with the piston removed and illustrating another embodiment;

FIGURE 5 is a transverse cross sectional view taken through the piston stopping member looking toward the muzzle of the embodiment of FIGURE 4;

FIGURE 6 is a longitudinal cross sectional view illustrating a still further embodiment;

FIGURE 7 is a longitudinal view in cross section showing further details of the embodiment of FIGURES 4 and 5. v

In the embodiment of FIGURE 1, the tool comprises a piston 1 slidably mounted in the barrel bore 10 wherein it may be driven forcibly from the initial position shown by explosion of the powder cartridge 5 until the working element, such as the punch 2 carried 'by the piston is projected through the opening 7 of the piston abutment sleeve 6 at the muzzle of the tool barrel to drive fastener F into support S.

The barrel comprises the helical coil, preferably a tension spring 3 having turns of heavy qualrilateral cross section, either rectangular, square or parallelogrammic, with adjacent turns normally closely fitting against each other to make a barrel with closed side walls at least adjacent the breech plug 4 having a chamber for receiving the cartridge 5. The coiled barrel 3 is joined at its ends to the plug 4 and sleeve 6 by any suitable means such as threads 8 and 9, respectively.

The closely fitting turns of the spring 3 provide a closed barrel having a cylindrical bore for carrying the piston l slidably and for applying the propellent gas generated by thecartridge 5 at least initially with confinement. The barrel remains closed for the most efiective application of the gas, unless overdriving occurs whereupon impact of the piston 1 upon sleeve 6 at the muzzle produces a separation of the turns beginning at the muzzle and traveling down the barrel a distance determined by the magnitude of the impact. The resultant venting acts to further alleviate the shock by relieving the residual gas pressure, particularly where this should be high.

The barrel may consist of a D-shaped coil or of a double or triple lead coil made in any suitable way as by helically slotting a cylinder and twisting it to close up the slots. Whatever coil form is used should provide the relatively smooth and continuous barrel bore 10 for piston 1.

In the form of the invention shown in FIGURES 2 and 3, the tool includes piston 11, its working element 12,

some thirty-six longitudinally extending barrel segments I for workpiece W. A large number of segments within practical limits are contemplated but sufficient in number to absorb the shock sufficiently to prevent overstress and rupture.

The segments preferably take the shape shown to include the piston stopping foot 17 and the breech sector 19. The barrel is assembled by staking the segments 13 in the collar 14 with a force fit. A shouldered portion of each segment and the collar is abutted as at 20 to give positive axial restraint Where needed in addition to the frictional retention. having a breech chamber for receiving powder cartridge 15, the smooth closed barrel bore and the piston stopping array of segment ends 17 defining the opening 18 through which element 12 acts upon the work when the piston 11 is driven at high velocity from the initial position shown.

In the embodiment piston 11 has a tapered forepart 31 which collides with the mating taper 3ft at the muzzle end of the segments in the event normal working conditions are absent. The action of the taper, particularly at very heavy blows, is to channel energy, in excess of that absorbable longitudinally in the segments, to dissipate itself in a radially outward elastic deformation of segment 13 and to cause the segments to separate circumferentially momentarily and vent the barrel to exhaust the residual gases and drop the driving pressure. Since this applies only in the event of an excess in the extreme, the taper must not be so steep as to overcome the friction on the slope so soon as to absorb substantially all of the shock by radial strain.

The venting action along with axial separation is obtainable in the tool barrel of FIGURE 1 because of the helical arrangement. Some circumferential separation occurs as the single helix of'a single lead or helixes of a plural lead barrel elongate, since the turns assume a steeper pitch becoming more widely separated circumferentially although not radially as in FIGURES 2-3.

It may be desirable to taper the segments 13 so as to initially obtain venting adjacent the muzzle, but not adjacent the collar 14. Alternately to avoid any venting another collar may surround the segment array at the muzzle or over more of the barrel length.

The tool barrel of FIGURES 4 and 5, also shown in FIGURE 7, is characterized by a bundle of rods or wires 23 which form an excellent shock absorbing barrel. At the breech (FIGURE 4) the rods are held between a breech block 21 with a barrel liner 22 and an outer breech collar 24 which may be fixed to the block 21. At the muzzle (FIGURE 5) the rods are held between a piston stopper sleeve 26 having opening 28 for the working punch, and a muzzle collar27. This collar may be positively secured to the sleeve 26 by any suitable fastening elements such as studs 29. The liner 22 is not secured at the muzzle so as not to interfered with the buffering action of the rods As shown in FIGURES 4 and 7, the breech also carries an explosive cartridge for fluid propellent generation.

In the embodiment of FIGURE 6 piston 41 rides in the bore of a barrel of multiplesleeve construction which effectively increases its length and imparts to it the ability to absorb tremendous shock repeatedly with greatly improved resistance to fracturing.

The barrel consists of a plurality of coaxial tubes such as the inner barrel liner 50, the intermediate tube 53 and the outer tube or sheath 55. At one end the liner 50 is fastened to breech plug 44, carrying cartridge 45, in any suitable way such as by welding at 51. At the muzzle end, liner 50 is fastened to tube 53 as by welding at 52. The intermediate tube 53 in turn is fastened at its other end adjacent breech plug 44 to sheath 55 as at the weld 54.

In this embodiment cartridge 45 is also carried, as are cartridges 5, 15, and 25 in the other embodiments, in a suitable communicating chamber and is ignitable by a firing pin or the like means, known to those skilled in the art typified by the aforementioned explosive tool patents.

At the muzzle the barrel has a piston stopping and orificed plug 4-7 fastened as by weld 57 to the muzzle end 56 of sheath 55 forming with plug 47 orifice 48 for projection of the working punch 42 carried by piston 41.

Shock forces generated in the event of collision put tubes 50 and in tension and tube 53 in compression.

Although three tubes are shown, five, seven or more Snap-ring 16 locks the assembly tube laminations. While this invention has utility as a shock absorber for any device wherein the piston is driven at a sufficiently high velocity with danger of high impact, it has particular utility in powder-actuated devices such as the stud driving tool herein referred to and described.

Since many other embodiments and various modifications of this invention may occur to those skilled in the art, it is to be understood that the foregoing is intended by way of illustration of a preferred embodiment and not as a limitation of the spirit and scope of the present invention except as set forth in the appended claims.

What is claimed is:

1. In a percussion tool, a piston, a driveable Work performing element adapted for impacting carried by said piston having an anterior shoulder, a barrel having a bore for carrying said piston, said piston being normally movable in said bore from an initial retracted position adjacent the breech of the bore over a working stroke to a final position adjacent the muzzle of the bore whereat said element is driven into the work and said impacting is terminated by normal piston and element stopping resistance encountered by said element during said impacting and over a return stroke back to said initial position, chamber means adjacent said breech end communicating with said bore between said end and piston for applying an explosive blast of high pressure fluid in said bore for forcefully propelling said piston over said Working stroke at high velocity, means carried on the barrel at said muzzle end for retaining said piston within said barrel by abutment with said shoulder and thereby stopping said piston adjacent said muzzle in the event of overtravel of said piston beyond said working stroke when said resistance is not fully encountered by said element, said barrel having a plurality of relatively narrow elongated segments in contiguity with adjacent segments to form said barrel as a normally circumferentially closed piston carrying cylinder, the long dimension of said segments extending over substantially all of the length of said barrel at least partially in the direction of said barrel length.

2. The tool of claim 1 wherein the segments extend helically around the barrel bore.

3. The tool of claim 1 wherein the segments are in the form of a circumferential array of contiguous wedge-shaped arcuate sectors which extend longitudinally about the bore and together form a cylindrical barrel bore side wall enclosure.

4. The tool of claim 3 wherein the anterior shoulder of the piston is of tapered configuration and wherein the ends of the sectors at the muzzle of the barrel have a complemcntary taper adapted upon impact with said piston shoulder to strain said sectors longitudinally for absorbing substantially all of the shock of said impact to avoid fracture of the tool whenever the driven piston overtravels said working stroke and to expand said segments freely, thereby separating them circumferentially and venting the barrel bore during said absorption of impact.

5. In an explosive actuated tool having a normally circumferentially uninterrupted barrel, a piston received and .slidably mounted in the bore of said barrel, means for admitting the high pressure gaseous products of ignition of an explosive charge as a propellant behind the piston to drive it towards the muzzle end of the barrel with high velocity and force, and a piston retaining means operatively connected to said barrel at the muzzle of the barrel, the improvement comprising said barrel being laminated at least intermediate its ends to form a plurality of substantially equal normally contiguous barrel laminations extending longitudinally of the barrel over substantially all its length, said laminations being effective to increase the longitudinal shock absorbing capacity of said barrel and its resistance to fracture to cushion the blow whenever the driven piston collides with said retaining means.

, 6. The tool of claim 5 wherein the laminations are in the form of a coaxial array of contiguous barrel tubes mounted in limited telescopic relationship, said array consisting of an inner tube, an outer tube, and at least one intermediate tube, said inner tube fixed at its breech end to a breech plug and fixed at its muzzle end to an adjacent intermediate tube, each said intermediate tube in turn being fixed alternately at its breech end and muzzle end to an adjacent tube, said outer tube fixed at its breech end to an adjacent intermediate tube and fixed at its muzzle end to the piston retaining means.

7. The tool of claim 6 wherein the tubes in axial compression are thicker than the tubes in axial tension.

8. In a percussion tool, a driveable work performing element carried by a piston having an anterior shoulder, a barrel having a bore for carrying said piston,.said

piston being movable in said bore from an initial retracted position adjacent the muzzle of the bore and over a return stroke back to said breech position, means adjacent said breech end for admitting an explosive blast of high pressure fluid into said bore for forcefully propelling said piston over said working stroke at high velocity, means carried on the barrel at said muzzle end for retaining said piston within said barrel by abutment with said shoulder and thereby stopping said piston adjacent said muzzle in the event of overtravel of said piston beyond said working stroke, said barrel including a bundle of relatively narrow elongated tie rods stacked so as to place adjacent tie rods in side-by-side contiguity with each other, said tie rods extending longitudinally with respect to the barrel length and circumferentially about said bore to form a normally circumferentially closed piston carrying cylinder, the long dimension of said segments extending over substantially all of the length of said barrel.

References Cited in the file of this patent UNITED STATES PATENTS 

